require 'active_support/core_ext/object/conversions'
require 'active_support/core_ext/object/extending'
require 'active_support/core_ext/object/instance_variables' # 对object进行一些关于instance_variables的扩展
require 'active_support/core_ext/object/metaclass' # 对object加上一个metaclass的壳,没什么特别的用途
require 'active_support/core_ext/object/misc'
